Hi John,
Yes, the second screw, which holds the vertical shaft in place, is the one I'm referring to. I have given thought to using a file to create a flat spot on this shaft, as you suggest, however with the additional issue of the vice not holding the hooks consistently, I'm seriously thinking about returning this vise and looking for something else, or just sticking with my Regal. It's not rotary, but I'm beginning to think that it doesn't really matter.